相关疑难解决方法(0)

我有这样的观点:

CREATE VIEW MyView AS
   SELECT Column FROM Table WHERE Value = 2;

我想让它更通用,它意味着将2变为变量.我试过这个:

CREATE VIEW MyView AS
   SELECT Column FROM Table WHERE Value = @MyVariable;

但MySQL不允许这样做.

我找到了一个丑陋的解决方法:

CREATE FUNCTION GetMyVariable() RETURNS INTEGER DETERMINISTIC NO SQL
BEGIN RETURN @MyVariable; END|

然后观点是:

CREATE VIEW MyView AS
   SELECT Column FROM Table WHERE Value = GetMyVariable();

但它看起来很糟糕,而且用法也很糟糕 - 我必须在每次使用视图之前设置@MyVariable.

有没有解决方案,我可以像这样使用:

SELECT Column FROM MyView(2) WHERE (...)

具体情况如下:我有一个表存储有关被拒绝请求的信息:

CREATE TABLE Denial
(
    Id INTEGER UNSIGNED AUTO_INCREMENT,
        PRIMARY KEY(Id),
    DateTime DATETIME NOT NULL,
    FeatureId MEDIUMINT …

有一个简单的Linq到EF:

var query = from p in _db.Posts
            where p.BlogtId == blogId
            select p;

它以这种形式生成SQL:

SELECT
`Extent1`.`PostId`, 
`Extent1`.`BlogId`, 
...
FROM `Posts` AS `Extent1`
 WHERE `Extent1`.`BlogId` = @p__linq__0

但是当我向此查询添加订单时

var query = from p in _db.Posts
            where p.BlogId == blogId
            orderby p.PublishDate
            select p;

它会生成此查询

SELECT
`Project1`.`PostId`, 
`Project1`.`BlogId`, 
...
FROM (SELECT
`Extent1`.`PostId`, 
`Extent1`.`BlogId`, 
...
FROM `Posts` AS `Extent1`
 WHERE `Extent1`.`BlogId` = @p__linq__0) AS `Project1`
 ORDER BY 
`Project1`.`PublishDate` ASC

为什么会生成子查询？MySQL中的此查询存在性能问题.MySQL正在尝试执行内部查询,该查询将数据库中的所有记录拉回,然后尝试对主题进行排序.

我需要一个解决方案来生成linq下面的sql

SELECT
`Extent1`.`PostId`, 
...
FROM `Posts` AS `Extent1`
 WHERE `Extent1`.`BlogId` = @p__linq__0 …